Method of recovering metal values from solutions.



PATENTED JULY 14, 1908.

METHGD 0F RECOVERING METAL VALUES FROM SOLUTIUNS.

W. A. HENDR APPLICATION FILED DE01. 1906.

m Millie UNITED @TATEB "PATENT OITIWOE.

WILBUR ALSON I-IENDRYX, OF DENVER, COLORADO.

METHOD OF RECOVERING METAL VALUES FROM SOLUTIONS.

Application filed December 1, 1906.

To all whom it may concern:

Be it known that I, INILBUR ALsoN HEN- DRYX, a citizen of the United States, residing at Hotel Metropole, in the city of Denver, in the county of Denver and State of Colorado, have invented new and useful Improvements in Methods of Recovering Metal Values from Solutions, of which the following is a specification.

The object of this invention is to provide a method of recovering metal values from solutions; the method being more particularly intended for the recovery of gold and silver from their cyanid solutions.

In the preferred embodiment of the invention there is added to the metal-bearing solution and thoroughly commingled therewith a c omminutidpreipit'ating agent'such Has ,gino dust, and the liquid is then passed through a suitablymdisposed filter under such conditions thatV 'a deposit containing the undissolved precipitating agentv collects uponfthe filter and is thereby brought into intimate contact withv successive portions" off'theY solution. Zinc dust is added insmall proportions at a time and preferably in a substantially continuous manner.

For a full understanding of the invention reference is made to the accompanying drawing showing one form of apparatus for carrying the same into effect, wherein:

Figure 1 is a vertical section, partly in elevation, of a form of device adapted for the separation of gold and silver from their cyanid or other solutions; and Fig. 2 is a vertiral section of the feed device on line 2, 2 of l In the drawing, 1 represents a tank which may be of sheet steel and adapted to withstand a considerable internal pressure of liquid; 2, 2 are filter cells vertically disposed in the tank, each cell having a bottom outlet 3 provided with a valve or cock as shown, all of said outlets preferably discharging into a common conduit 4 for the filtered liquid. As shown each filter cell comprises an open frame 5 having lateral filtering walls 6 of canvas or other suitable material, and a filling 7 of material such as cocoa-matting or the like which is adapted to sustain the filter walls while providing a free passage for the solution.

The tank is shown as surmounted by a casing 10 containing a revoluble shaft 11 mounted in upper and lower bearings 12, 13,

' and carrying helical agitating blades 14; as

Specification of Letters Patent.

Patented July 14, 1908.

Serial No. 345,920.

shown the casing is provided with stationary baffles 15, the combined effect of the blades and baflies being to effect a thorough agitation of the material traversing the casing, and the precipitation of the great-er portion of the values; the helical blades serve also as a pump to establish a current of the liquid or solution through the pipe 8 communicating with the tank 1 and the desired pressure of the same in the tank. An inlet pipe 16 is arranged adjacent the lower end of the casing.

17 is a hopper adapted to contain the precipitating agent and to effect its regulated and substantially continuous discharge into the metal-bearing solution conveyed by the pipe 16. The hopper 17 is provided with an inclined bottoni 18 and a central discharge pipe 19 leading to the pipe 16; a recessed feed-wheel 20 of usual construction is mounted in the discharge aperture of the hopper upon a shaft 21. By rotation of the recessed wheel measured or regulated charges of the material in the hopper are discharged into the stream of solution in the pipe 16 as will be readily understood. The feed-hopper is shown as provided with an agitating device comprising upper and lower sprocket wheels 22, 23 carrying a sprocket chain 24 which passes through the body of material in the hopper and by its movement thoroughly agitates the same and prevents arching or other interruption of the feed. The sprocket wheel 23 is loosely mounted on a shaft 25, the sprocket 22 bein@- rigidly mounted on the shaft 26. Speed-pu leys 27, 28 are secured upon the shafts 26 and 21, respectively, and are connected by a belt 29. The mechanism may be driven by a pulley 30 on shaft 26, or otherwise. By means of the speed-pulleys, and also by blocking one or more of the recesses in the wheel 20, a close regulation of the rate of feed of the precipitating agent may be secured.

Assuming the apparatus to be used for precipitating gold and silver from a cyanid solution, the operation is as follows: Zinc dust or fume is placed in the hopper 17 and the metal-bearing solution is admitted to the pipe 16. By operation of the feed-device in the hopper Zinc dust is fed to the flowing solution in the proportion required to precipitate the metallic values therein or in slight excess of such proportion. In the casing 10 the solution and preci itant are thoroughly commingled by the b ades and baflies and the greater portion of the metallic values is zinc and any gold or silver which may reseparated. The liquid carrying the precipitated values and undissolved precipitant in suspension passes to the tank l, from which the clear solution flows through the filter cells to the conduit 4, to be returned to the leaching vats after any required treatment for the restoration of its solvent power.

The undissolved residue of the precipitant, together with the precipitated values, collects upon the canvas or other ltering medium 6 in the form of a porous coating through which all further portions of the liquid must pass: in this coating the solution is brought into intimate contact with the undissolved main in solution is separated. After a suflicient quantity of precipitate has been collected the liquid contents of the tank are discharged and the coating is dislodged from the filter, as by a stream of water admitted through the elongated hand-hold 31, and the metals are withdrawn through valved outlet 9 and refined in any suitable manner.

It will be noted that the discharge pipe 8 from the casing 10 extends nearly tothe bottom of the tank l and is substantially central therein. The purpose of this arrangement is to prevent any considerable proportion of the zinc or the precipitated values from depositing on the bottom of the tank, and to cause the same to form a cake or deposit upon the filtering surfaces as above described.

The above-described method is found in practice to be highly efficient and very economical as regards the consumption of zinc, the constant feeding of small proportions of the precipitant to the solution effectually avoiding the fouling which necessarily occurs when relatively large proportions of zinc are added to metal-bearing solutions carrying considerable amounts of base metals.

I claim:

l. The method of recovering metal values from solutions which consists in adding a coinminuted precipitating agent to a stream of the solution, commingling it therewith and thereby precipitating a portion of the values, establishing a filtering layer containing the precipitate and the undissolved precipitating agent, and passing portions of the solution through said layer whereby a complete separation of the metallic values is secured.

2. The method of recovering metal values from cyanid and other solutions containing the same which consists in adding zinc dust to a stream of the solution and thoroughly commingling it therewith, thereby precipitating a portion of the values, establishing a filtering layer containing the separated metals and the undissolved zinc7 and passing portions of the solution through said layer whereby a complete separation of the metallic values is secured.

In testimony whereof I affix my signature in presence of two witnesses.

WILBUR ALSON HENDRYX.

Witnesses:

THEoDoRA WELLS, CnAs. R. DAvins. 

